During use of batteries, abnormal conditions that threaten safety of the batteries such as overcharging, over-discharging, charging or discharging at an overlarge current often occur. These abnormal conditions have a serious effect on the service life of the batteries and may even cause serious problems such as electrolyte leakage or explosion of the batteries. In order to avoid these abnormal conditions, a battery protection circuit is usually disposed in a battery management system to protect the batteries.
Current battery protection circuits usually operate in two way: the software and the hardware. A battery protection circuit of the software type uses software/MCU to acquire a voltage of a battery, compares the voltage with a preset threshold and then takes a corresponding protective action; and a battery protection circuit of the hardware type uses a comparator to provide a fixed threshold for comparison and then takes a corresponding protective action.
The battery protection circuit of the software type is flexible to use because the protection program thereof can be altered for many times, and the preset threshold can be adjusted depending on different battery types and different demands. However, it has a relatively large overall power consumption, and is easily to be interfered or fleeting, each one of these makes it impossible to provide normal protection any longer. On the other hand, the battery protection circuit of the hardware type features stable operation, but is less flexible to use because it cannot be adjusted efficiently depending on the customer's practical needs and does not allow for alteration of parameters.
Additionally, in order to ensure the battery safety, a redundant battery protection circuits may be disposed in some battery management systems. For example, two battery protection circuits in a hardware form, or one battery protection circuit in a software form in combination with one battery protection circuit in a hardware form are used. However, such a redundant protection scheme considerably increases the power consumption and the cost of the system.
Accordingly, an urgent need exists in the art to develop a novel battery protection circuit that can improve the aforesaid problems.